Aqueous binder compositions

ABSTRACT

An aqueous binder composition is disclosed that comprises at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000 Daltons; a primary cross-linking agent comprising at least two carboxylic acid groups; and a secondary cross-linking agent comprising a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000 Daltons.

RELATED APPLICATIONS

This application claims priority to and any benefit of U.S. Provisional Patent Application No. 62/569,775, filed Oct. 9, 2017, the content of which is incorporated herein by reference in its entirety.

BACKGROUND

Aqueous binder compositions are traditionally utilized in the formation of woven and non-woven fibrous products, such as insulation products, composite products, wood fiber board, and the like. Insulation products, for example fiberglass and mineral wool insulation products, are typically manufactured by fiberizing a molten composition of polymer, glass, or other mineral and spinning fine fibers from a fiberizing apparatus, such as a rotating spinner. To form an insulation product, fibers produced by a rotating spinner are drawn downwardly from the spinner towards a conveyor by a blower. As the fibers move downward, a binder material is sprayed onto the fibers and the fibers are collected into a high loft, continuous blanket on the conveyor. The binder material gives the insulation product resiliency for recovery after packaging and provides stiffness and handleability so that the insulation product can be handled and applied as needed in the insulation cavities of buildings. The binder composition also provides protection to the fibers from interfilament abrasion and promotes compatibility between the individual fibers. The blanket containing the binder-coated fibers is then passed through a curing oven and the binder is cured to set the blanket to a desired thickness.

After the binder has cured, the fiber insulation may be cut into lengths to form individual insulation products, and the insulation products may be packaged for shipping to customer locations.

Fiberglass insulation products prepared in this manner can be provided in various forms including batts, blankets, and boards (heated and compressed batts) for use in different applications. As the batt of binder-coated fibers emerges from the forming chamber, it will tend to expand as a result of the resiliency of the glass fibers. The expanded batt is then typically conveyed to and through a curing oven in which heated air is passed through the insulation product to cure the binder. In addition to curing the binder, within the curing oven, the insulation product may be compressed with flights or rollers to produce the desired dimensions and surface finish on the resulting blanket, batt or board product.

Phenol-formaldehyde (PF) binder compositions, as well as PF resins extended with urea (PUF resins), have been traditionally used in the production of fiberglass insulation products. Insulation boards, also known as “heavy density” products, such as ceiling board, duct wrap, duct liners, and the like have utilized phenol-formaldehyde binder technology for the production of heavy density products that are inexpensive and have acceptable physical and mechanical properties. However, formaldehyde binders emit undesirable emissions during the manufacturing of the fiberglass insulation.

As an alternative to formaldehyde-based binders, certain formaldehyde-free formulations have been developed for use as a binder in fiberglass insulation products. One of the challenges to developing suitable alternatives, however, is to identify formulations that have comparable mechanical and physical properties, while avoiding undesirable properties, such as discoloration. Such property challenges include hot/humid performance, stiffness, bond strength, processability (viscosity, cutting, sanding, edge painting), and achieving a light color without yellowing.

Accordingly, there is a need for an environmentally friendly, formaldehyde-free binder composition for use in the production of insulation products without experiencing a loss in physical and mechanical properties.

SUMMARY

Various exemplary aspects of the inventive concepts are directed to an aqueous binder composition comprising at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000; a cross-linking agent comprising at least two carboxylic acid groups; and a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000. The binder composition has a pH after cure between 5 and 9 and achieves a b* color value, using L*a*b* coordinates, of less than 45.

In some exemplary embodiments, the cross-linking agent is a polymeric polycarboxylic acid, such as a homopolymer of copolymer of acrylic acid. The cross-linking agent may be present in the binder composition in an amount from about 50 wt. % to about 85 wt. %, based on the total solids content of the aqueous binder composition. In some exemplary embodiments, the cross-linking agent is present in the binder composition in an amount from about 65 wt. % to about 80 wt. %, based on the total solids content of the aqueous binder composition.

In some exemplary embodiments, the long-chain polyol is selected from the group consisting of partially or fully hydrolyzed polyvinyl alcohol and polyvinyl acetate. The long-chain polyol may be present in the binder composition in an amount from about 5 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition. In various exemplary embodiments, the short-chain polyol comprises one or more of a sugar alcohol, 2,2-bis(methylol)propionic acid, tri(methylol)propane, and a short-chain alkanolamine. When the short-chain polyol comprises a sugar alcohol, the sugar alcohol may be selected from the group consisting of glycerol, erythritol, arabitol, xylitol, sorbitol, maltitol, mannitol, iditol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritol, syrups thereof, and mixtures thereof.

In various exemplary embodiments, the short-chain polyol is present in the binder composition in an amount from about 3 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition.

Other exemplary aspects of the inventive concepts are directed to an insulation product comprising a plurality of randomly oriented fibers and an aqueous binder composition at least partially coating the fibers. The binder composition may comprise at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000 Daltons; a cross-linking agent comprising at least two carboxylic acid groups; and a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000 Daltons. In some exemplary embodiments, the binder composition has a pH after cure between 5 and 9 and achieves a b* color value, using L*a*b* coordinates, of less than 45.

The fibers of the insulation products may comprise one or more of mineral fibers, natural fibers, and synthetic fibers, and in some embodiments, the fibers comprise glass fibers.

The insulation product may have a thickness of about 1 inch and a density of about 6 lbs/ft3. In some exemplary embodiments, the insulation product has a flexural elastic modulus of at least 40 psi.

Various exemplary embodiments of the present inventive concepts are directed to a method for controlling color in insulation products formed using a formaldehyde-free binder composition. The method may comprise the following steps: preparing an aqueous, formaldehyde-free binder composition and curing the binder composition to achieve a b* color value, using L*a*b* coordinates, of less than 45 and a cured binder pH of between 5 and 9. The binder composition may comprise at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000 Daltons; a cross-linking agent comprising at least two carboxylic acid groups; and a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000 Daltons.

In some exemplary embodiments, prior to curing, the pH is adjusted by 0.25 to 1.5 pH units. The pH adjustment may occur by the addition of one or more of a non-volatile base and alkaline reclaimed water.

In some exemplary embodiments, the cross-linking agent is a polymeric polycarboxylic acid, such as a homopolymer of copolymer of acrylic acid. The cross-linking agent may be present in the binder composition in an amount from about 50 wt. % to about 85 wt. %, based on the total solids content of the aqueous binder composition. In some exemplary embodiments, the cross-linking agent is present in the binder composition in an amount from about 65 wt. % to about 80 wt. %, based on the total solids content of the aqueous binder composition.

In some exemplary embodiments, the long-chain polyol is selected from the group consisting of partially or fully hydrolyzed polyvinyl alcohol and polyvinyl acetate. The long-chain polyol may be present in the binder composition in an amount from about 5 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition. In various exemplary embodiments, the short-chain polyol comprises one or more of a sugar alcohol, 2,2-bis(methylol)propionic acid, tri(methylol)propane, and a short-chain alkanolamine. When the short-chain polyol comprises a sugar alcohol, the sugar alcohol may be selected from the group consisting of glycerol, erythritol, arabitol, xylitol, sorbitol, maltitol, mannitol, iditol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritol, syrups thereof, and mixtures thereof.

In various exemplary embodiments, the short-chain polyol is present in the binder composition in an amount from about 3 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition.

Numerous other aspects, advantages, and/or features of the general inventive concepts will become more readily apparent from the following detailed description of exemplary embodiments and from the accompanying drawings being submitted herewith.

BRIEF DESCRIPTION OF THE DRAWINGS

The general inventive concepts, as well as illustrative embodiments and advantages thereof, are described below in greater detail, by way of example, with reference to the drawings in which:

FIG. 1 illustrates exemplary fiberglass sheet strips coated with cured binder compositions according to the present application, with varying pH and cure color.

FIG. 2 graphically illustrates color L*a*b* coordinates for exemplary binder compositions as the pH of the binder is increased.

FIG. 3 graphically illustrates the flexural stress/wt./LOI for fiberglass insulation made with exemplary cured binder compositions having varying ratios of molar equivalent carboxylic acid groups/hydroxyl groups and long-chain polyol/short-chain polyol.

FIG. 4 graphically illustrates the color b* value for fiberglass insulation made with exemplary cured binder compositions having varying ratios of molar equivalent carboxylic acid groups/hydroxyl groups and long-chain polyol/short-chain polyol.

FIG. 5 graphically illustrates the tensile force/LOI for fiberglass made with exemplary binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/0.1 and varying long-chain polyol/short-chain polyol ratios.

FIG. 6 graphically illustrates both the % water soluble material post-cure and color b* value for exemplary binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/0.1 and varying long-chain polyol/short-chain polyol ratios.

FIG. 7 graphically illustrates the tensile force/LOI for exemplary cured binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/1.5 and varying long-chain polyol/short-chain polyol ratios.

FIG. 8 graphically illustrates both the % water soluble material post-cure and color b* value for exemplary binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/1.5 and varying long-chain polyol/short-chain polyol ratios.

FIG. 9 graphically illustrates the tensile force/LOI for exemplary cured binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/0.5 and varying long-chain polyol/short-chain polyol ratios.

FIG. 10 graphically illustrates both the % water soluble material post-cure and color b* value for exemplary binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/0.5 and varying long-chain polyol/short-chain polyol ratios.

FIG. 11 graphically illustrates the tensile force/LOI for exemplary cured binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/0.1 and varying long-chain polyol/short-chain polyol ratios.

FIG. 12 graphically illustrates both the % water soluble material post-cure and color b* value for exemplary binder compositions having a ratio of molar equivalent carboxylic acid groups/hydroxyl groups of 1/1 and varying long-chain polyol/short-chain polyol ratios.

FIG. 13 graphically illustrates the tensile force/LOI for exemplary cured binder compositions having varied ratios of molar equivalent carboxylic acid groups/hydroxyl groups.

FIG. 14 graphically illustrates the flexural elastic modulus for plant trial boards formed using various binder compositions in accordance with the subject application, compared to conventional starch-hybrid binder compositions and phenol urea formaldehyde-based binder compositions.

FIG. 15 graphically illustrates the sag for 4′×4′ fiberglass insulation ceiling board tiles formed using various binder compositions in accordance with the subject application, compared to conventional starch-hybrid binder compositions and phenol urea formaldehyde-based binder compositions under hot/humid conditions.

FIG. 16 graphically illustrates the compressive strength of plant trial board products, formed using various binder compositions in accordance with the subject application, compared to conventional starch-hybrid binder compositions and phenol urea formaldehyde-based binder compositions.

FIG. 17 graphically illustrates the bond strength at break of plant trial board products formed using various binder compositions in accordance with the subject application, compared to conventional starch-hybrid binder compositions and phenol urea formaldehyde-based binder compositions.

DETAILED DESCRIPTION

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these exemplary embodiments belong. The terminology used in the description herein is for describing exemplary embodiments only and is not intended to be limiting of the exemplary embodiments. Accordingly, the general inventive concepts are not intended to be limited to the specific embodiments illustrated herein. Although other methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein.

As used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Unless otherwise indicated, all numbers expressing quantities of ingredients, chemical and molecular properties, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present exemplary embodiments. At the very least each numerical parameter should be construed in light of the number of significant digits and ordinary rounding approaches.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the exemplary embodiments are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Every numerical range given throughout this specification and claims will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

The present disclosure relates to formaldehyde-free aqueous binder compositions for use in the manufacture of insulation products that have comparable or improved mechanical and physical performance, compared to products manufactured with traditional formaldehyde-based binder compositions. The formaldehyde-free binder composition may be used in the manufacture of fiber insulation products and related products, such as thin fiber-reinforced mats (all hereinafter referred to generically as fiber reinforced products) and glass fiber or mineral wool products, especially fiberglass or mineral wool insulation products, made with the cured formaldehyde-free binder. Other products may include composite products, wood fiber board products, metal building insulation, pipe insulation, ceiling board, ceiling tile, “heavy density” products, such as ceiling board, duct wrap, duct liners, and also “light density” products.

The present disclosure further relates to a method for controlling the color of products made using a formaldehyde-free binder composition. Traditional phenolic binders are characterized by the formation of an orange-red color upon cure. The color intensity varies with binder concentration and cure temperature, often resulting in a marbled appearance, which is a disadvantage in architectural, exposed applications or in applications that utilize a thin, light colored facing.

In some exemplary embodiments, the formaldehyde-free aqueous binder composition includes at least one long-chain polyol, and at least one primary cross-linking agent, and at least one secondary cross-linking agent comprising at least one short-chain polyol.

The primary crosslinking agent may be any compound suitable for crosslinking the polyol. In exemplary embodiments, the primary crosslinking agent has a number average molecular weight greater than 90 Daltons, from about 90 Daltons to about 10,000 Daltons, or from about 190 Daltons to about 5,000 Daltons. In some exemplary embodiments, the crosslinking agent has a number average molecular weight of about 2,000 Daltons to 5,000 Daltons, or about 4,000 Daltons. Non-limiting examples of suitable crosslinking agents include materials having one or more carboxylic acid groups (—COOH), such as polycarboxylic acids (and salts thereof), anhydrides, monomeric and polymeric polycarboxylic acid with anhydride (i.e., mixed anhydrides), and homopolymer or copolymer of acrylic acid, such as polyacrylic acid (and salts thereof) and polyacrylic acid based resins such as QR-1629S and Acumer 9932, both commercially available from The Dow Chemical Company. Acumer 9932 is a polyacrylic acid/sodium hypophosphite resin having a molecular weight of about 4000 and a sodium hypophosphite content of 6-7% by weight. QR-1629S is a polyacrylic acid/glycerin mixture.

The primary cross-linking agent may, in some instances, be pre-neutralized with a neutralization agent. Such neutralization agents may include organic and/or inorganic bases, such sodium hydroxide, ammonium hydroxide, and diethylamine, and any kind of primary, secondary, or tertiary amine (including alkanol amine). In various exemplary embodiments, the neutralization agents may include at least one of sodium hydroxide and triethanolamine.

In some exemplary embodiments, the primary crosslinking agent is present in the aqueous binder composition in at least 50 wt. %, based on the total solids content of the aqueous binder composition, including, without limitation at least 55 wt. %, at least 60 wt. %, at least 63 wt. %, at least 65 wt. %, at least 70 wt. %, at least 73 wt. %, at least 75 wt. %, at least 78 wt. %, and at least 80 wt. %. In some exemplary embodiments, the primary crosslinking agent is present in the aqueous binder composition in an amount from 50% to 85% by weight, based on the total solids content of the aqueous binder composition, including without limitation 60% to 80% by weight, 62% to 78% by weight, and 65% to 75% by weight.

In some exemplary embodiments, the long-chain polyol comprises a polyol having at least two hydroxyl groups having a number average molecular weight of at least 2,000 Daltons, such as a molecular weight between 3,000 Daltons and 4,000 Daltons. In some exemplary embodiments, the long-chain polyol comprises one or more of a polymeric polyhydroxy compound, such as a polyvinyl alcohol, polyvinyl acetate, which may be partially or fully hydrolyzed, or mixtures thereof. Illustratively, when a partially hydrolyzed polyvinyl acetate serves as the polyhydroxy component, an 80%-89% hydrolyzed polyvinyl acetate may be utilized, such as, for example Poval® 385 (Kuraray America, Inc.) and Sevol™ 502 (Sekisui Specialty Chemicals America, LLC), both of which are about 85% (Poval® 385) and 88% (Selvol™ 502) hydrolyzed.

The long-chain polyol may be present in the aqueous binder composition in an amount up to about 30% by weight total solids, including without limitation, up to about 28%, 25%, 20%, 18%, 15%, and 13% by weight total solids. In some exemplary embodiments, the long-chain polyol is present in the aqueous binder composition in an amount from 5.0% to 30% by weight total solids, including without limitation 7% to 25%, 8% to 20%, 9% to 18%, and 10% to 16%, by weight total solids.

Optionally, the aqueous binder composition includes a secondary crosslinking agent, such as a short-chain polyol. The short-chain polyol may comprise a water-soluble compound having a molecular weight of less than 2,000 Daltons, including less than 750 Daltons, less than 500 Daltons and having a plurality of hydroxyl (—OH) groups. Suitable short-chain polyol components include sugar alcohols, 2,2-bis(methylol)propionic acid (bis-MPA), tri(methylol)propane (TMP), and short-chain alkanolamines, such as triethanolamine. In some exemplary embodiments, the short-chain polyol serves as a viscosity reducing agent, which breaks down the intra and inter molecular hydrogen bonds between the long-chain polyol molecules (e.g., polyvinyl alcohol) and thus lowers the viscosity of the composition. However, as these small-chain polyol molecules have similar structures to the long-chain polyols, they can react similarly with cross-linking agents, thus they do not negatively impact the binder and product performance.

Sugar alcohol is understood to mean compounds obtained when the aldo or keto groups of a sugar are reduced (e.g. by hydrogenation) to the corresponding hydroxy groups. The starting sugar might be chosen from monosaccharides, oligosaccharides, and polysaccharides, and mixtures of those products, such as syrups, molasses and starch hydrolyzates. The starting sugar also could be a dehydrated form of a sugar. Although sugar alcohols closely resemble the corresponding starting sugars, they are not sugars. Thus, for instance, sugar alcohols have no reducing ability, and cannot participate in the Maillard reaction typical of reducing sugars. In some exemplary embodiments, the sugar alcohol includes glycerol, erythritol, arabitol, xylitol, sorbitol, maltitol, mannitol, iditol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritol, syrups thereof and mixtures thereof. In various exemplary embodiments, the sugar alcohol is selected from glycerol, sorbitol, xylitol, and mixtures thereof. In some exemplary embodiments, the secondary cross-linking agent is a dimeric or oligomeric condensation product of a sugar alcohol. In various exemplary embodiments, the condensation product of a sugar alcohol is isosorbide. In some exemplary embodiments, the sugar alcohol is a diol or glycol.

In some exemplary embodiments, the short-chain polyol is present in the aqueous binder composition in an amount up to about 30% by weight total solids, including without limitation, up to about 25%, 20%, 18%, 15%, 13%, 11%, and 10% by weight total solids. In some exemplary embodiments, the short-chain polyol is present in the aqueous binder composition in an amount from 0 to 30% by weight total solids, including without limitation 2% to 30%, 3% to 25%, 5% to 20%, 8% to 18%, and 9% to 15%, by weight total solids.

In various exemplary embodiments, the long-chain polyol, crosslinking agent, and small-chain polyol are present in amounts such that the ratio of the number of molar equivalents of carboxylic acid groups, anhydride groups, or salts thereof to the number of molar equivalents of hydroxyl groups is from about 1/0.05 to about 1/5, such as from about 1/0.08 to about 1/2.0, from about 1/0.1 to about 1/1.5, and from about 1/0.3 to about 1/0.66. It has surprisingly been discovered, however, that within this ratio, the ratio of long-chain polyol to short-chain polyol effects the performance of the binder composition, such as the tensile strength and water solubility of the binder after cure. For instance, it has been discovered that a ratio of long-chain polyol to short-chain polyol between about 0.1/0.9 to about 0.9/0.1, such as between about 0.3/0.7 and 0.7/0.3, or between about 0.4/0.6 and 0.6/0.4 provides a balance of desirable mechanical properties and physical color properties. In various exemplary embodiments, the ratio of long-chain polyol to short-chain polyol is approximately 0.5/0.5. The ratio of long-chain polyol to short-chain polyol may be optimized such that particular properties are optimized, depending on the needs of an end-use application. For instance, as the concentration of long-chain polyol decreases, the color intensity of the binder decreases (more white). However, lowering the long-chain polyol concentration may also decrease the tensile strength of a product formed with the binder composition. Thus, a balance between various properties has been unexpectedly struck within the ratios disclosed herein.

Optionally, the aqueous binder composition may include an esterification catalyst, also known as a cure accelerator. The catalyst may include inorganic salts, Lewis acids (i.e., aluminum chloride or boron trifluoride), Bronsted acids (i.e., sulfuric acid, p-toluenesulfonic acid and boric acid) organometallic complexes (i.e., lithium carboxylates, sodium carboxylates), and/or Lewis bases (i.e., polyethyleneimine, diethylamine, or triethylamine). Additionally, the catalyst may include an alkali metal salt of a phosphorous-containing organic acid; in particular, alkali metal salts of phosphorus acid, hypophosphorus acid, or polyphosphoric. Examples of such phosphorus catalysts include, but are not limited to, sodium hypophosphite, sodium phosphate, potassium phosphate, disodium pyrophosphate, tetrasodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, potassium phosphate, potassium tripolyphosphate, sodium trimetaphosphate, sodium tetrametaphosphate, and mixtures thereof. In addition, the catalyst or cure accelerator may be a fluoroborate compound such as fluoroboric acid, sodium tetrafluoroborate, potassium tetrafluoroborate, calcium tetrafluoroborate, magnesium tetrafluoroborate, zinc tetrafluoroborate, ammonium tetrafluoroborate, and mixtures thereof. Further, the catalyst may be a mixture of phosphorus and fluoroborate compounds. Other sodium salts such as, sodium sulfate, sodium nitrate, sodium carbonate may also or alternatively be used as the catalyst.

The catalyst may be present in the aqueous binder composition in an amount from about 0% to about 10% by weight of the total solids in the binder composition, including without limitation, amounts from about 1% to about 5% by weight, or from about 2% to about 4.5% by weight, or from about 2.8% to about 4.0% by weight, or from about 3.0% to about 3.8% by weight.

Optionally, the aqueous binder composition may contain at least one coupling agent. In at least one exemplary embodiment, the coupling agent is a silane coupling agent. The coupling agent(s) may be present in the binder composition in an amount from about 0.01% to about 5% by weight of the total solids in the binder composition, from about 0.01% to about 2.5% by weight, from about 0.05% to about 1.5% by weight, or from about 0.1% to about 1.0% by weight.

Non-limiting examples of silane coupling agents that may be used in the binder composition may be characterized by the functional groups alkyl, aryl, amino, epoxy, vinyl, methacryloxy, ureido, isocyanato, and mercapto. In exemplary embodiments, the silane coupling agent(s) include silanes containing one or more nitrogen atoms that have one or more functional groups such as amine (primary, secondary, tertiary, and quaternary), amino, imino, amido, imido, ureido, or isocyanato. Specific, non-limiting examples of suitable silane coupling agents include, but are not limited to, aminosilanes (e.g., triethoxyaminopropylsilane; 3-aminopropyl-triethoxysilane and 3-aminopropyl-trihydroxysilane), epoxy trialkoxysilanes (e.g., 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane), methyacryl trialkoxysilanes (e.g., 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane), hydrocarbon trialkoxysilanes, amino trihydroxysilanes, epoxy trihydroxysilanes, methacryl trihydroxy silanes, and/or hydrocarbon trihydroxysilanes. In one or more exemplary embodiment, the silane is an aminosilane, such as γ-aminopropyltriethoxysilane.

Optionally, the aqueous binder composition may include a process aid. The process aid is not particularly limiting so long as the process aid functions to facilitate the processing of the fibers formation and orientation. The process aid can be used to improve binder application distribution uniformity, to reduce binder viscosity, to increase ramp height after forming, to improve the vertical weight distribution uniformity, and/or to accelerate binder de-watering in both forming and oven curing process. The process aid may be present in the binder composition in an amount from 0 to about 10% by weight, from about 0.1% to about 5.0% by weight, or from about 0.3% to about 2.0% by weight, or from about 0.5% to 1.0% by weight, based on the total solids content in the binder composition. In some exemplary embodiments, the aqueous binder composition is substantially or completely free of any processing aids.

Examples of processing aids include defoaming agents, such as, emulsions and/or dispersions of mineral, paraffin, or vegetable oils; dispersions of polydimethylsiloxane (PDMS) fluids, and silica which has been hydrophobized with polydimethylsiloxane or other materials. Further processing aids may include particles made of amide waxes such as ethylenebis-stearamide (EBS) or hydrophobized silica. A further process aid that may be utilized in the binder composition is a surfactant. One or more surfactants may be included in the binder composition to assist in binder atomization, wetting, and interfacial adhesion.

The surfactant is not particularly limited, and includes surfactants such as, but not limited to, ionic surfactants (e.g., sulfate, sulfonate, phosphate, and carboxylate); sulfates (e.g., alkyl sulfates, ammonium lauryl sulfate, sodium lauryl sulfate (SDS), alkyl ether sulfates, sodium laureth sulfate, and sodium myreth sulfate); amphoteric surfactants (e.g., alkylbetaines such as lauryl-betaine); sulfonates (e.g., dioctyl sodium sulfosuccinate, perfluorooctanesulfonate, perfluorobutanesulfonate, and alkyl benzene sulfonates); phosphates (e.g., alkyl aryl ether phosphate and alkyl ether phosphate); carboxylates (e.g., alkyl carboxylates, fatty acid salts (soaps), sodium stearate, sodium lauroyl sarcosinate, carboxylate fluorosurfactants, perfluoronanoate, and perfluorooctanoate); cationic (e.g., alkylamine salts such as laurylamine acetate); pH dependent surfactants (primary, secondary or tertiary amines); permanently charged quaternary ammonium cations (e.g., alkyltrimethylammonium salts, cetyl trimethylammonium bromide, cetyl trimethylammonium chloride, cetylpyridinium chloride, and benzethonium chloride); and zwitterionic surfactants, quaternary ammonium salts (e.g., lauryl trimethyl ammonium chloride and alkyl benzyl dimethylammonium chloride), and polyoxyethylenealkylamines.

Suitable nonionic surfactants that can be used in conjunction with the binder composition include polyethers (e.g., ethylene oxide and propylene oxide condensates, which include straight and branched chain alkyl and alkaryl polyethylene glycol and polypropylene glycol ethers and thioethers); alkylphenoxypoly(ethyleneoxy)ethanols having alkyl groups containing from about 7 to about 18 carbon atoms and having from about 4 to about 240 ethyleneoxy units (e.g., heptylphenoxypoly(ethyleneoxy) ethanols, and nonylphenoxypoly(ethyleneoxy) ethanols); polyoxyalkylene derivatives of hexitol including sorbitans, sorbides, mannitans, and mannides; partial long-chain fatty acids esters (e.g., polyoxyalkylene derivatives of sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, and sorbitan trioleate); condensates of ethylene oxide with a hydrophobic base, the base being formed by condensing propylene oxide with propylene glycol; sulfur containing condensates (e.g., those condensates prepared by condensing ethylene oxide with higher alkyl mercaptans, such as nonyl, dodecyl, or tetradecyl mercaptan, or with alkylthiophenols where the alkyl group contains from about 6 to about 15 carbon atoms); ethylene oxide derivatives of long-chain carboxylic acids (e.g., lauric, myristic, palmitic, and oleic acids, such as tall oil fatty acids); ethylene oxide derivatives of long-chain alcohols (e.g., octyl, decyl, lauryl, or cetyl alcohols); and ethylene oxide/propylene oxide copolymers.

In at least one exemplary embodiment, the surfactants include one or more of Dynol 607, which is a 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, SURFONYL® 420, SURFONYL® 440, and SURFONYL® 465, which are ethoxylated 2,4,7,9-tetramethyl-5-decyn-4,7-diol surfactants (commercially available from Evonik Corporation (Allentown, Pa.)), Stanfax (a sodium lauryl sulfate), Surfynol 465 (an ethoxylated 2,4,7,9-tetramethyl 5 decyn-4,7-diol), Triton™ GR-PG70 (1,4-bis(2-ethylhexyl) sodium sulfosuccinate), and Triton™ CF-10 (poly(oxy-1,2-ethanediyl), alpha-(phenylmethyl)-omega-(1,1,3,3-tetramethylbutyl)phenoxy).

The binder composition may also include organic and/or inorganic acids and bases as pH adjusters in an amount sufficient to adjust the pH to a desired level. The pH may be adjusted depending on the intended application, to facilitate the compatibility of the ingredients of the binder composition, or to function with various types of fibers. In some exemplary embodiments, the pH adjuster is utilized to adjust the pH of the binder composition to an acidic pH. Examples of suitable acidic pH adjusters include inorganic acids such as, but not limited to sulfuric acid, phosphoric acid and boric acid and also organic acids like p-toluenesulfonic acid, mono- or polycarboxylic acids, such as, but not limited to, citric acid, acetic acid and anhydrides thereof, adipic acid, oxalic acid, and their corresponding salts. Also, inorganic salts that can be acid precursors. The acid adjusts the pH, and in some instances, as discussed above, acts as a crosslinking agent. In other exemplary embodiment, organic and/or inorganic bases, can be included to increase the pH of the binder composition. In some exemplary embodiments, the bases may be a volatile or non-volatile base. Exemplary volatile bases include, for example, ammonia and alkyl-substituted amines, such as methyl amine, ethyl amine or 1-aminopropane, dimethyl amine, and ethyl methyl amine. Exemplary non-volatile bases include, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, and t-butylammonium hydroxide.

The pH of the binder composition cures under acidic conditions and has a natural pH between about 2.0-3.0. At this pH, the binder composition may have an orange-red color upon cure, and this color varies in appearance due to binder concentration and cure temperature. It is believed that the long-chain polyol (e.g., polyvinyl alcohol) undergoes rapid chain-stripping elimination of water at temperatures above its decomposition temperature, which causes the color to change from yellow to orange, to dark brown, to black. This reaction is acid-catalyzed, which leads to most carboxylic acid and polyvinyl alcohol-containing binders to have a yellow-orange color.

Such a color and varied appearance may be undesirable for some applications, particularly applications that involve exposed boards. However, it has been unexpectedly discovered that raising the pH slightly, such as by 0.25 to 2.0 pH units, causes the color to significantly lighten and reduces the varied or marbled appearance. In particular, the color appearance can be shifted from an orange-red color to an off-white color by increasing the pH by 0.5 to 1.5 pH units, or by 1.0 to 1.5 pH units. After cure, such as binder composition has a pH from about 5.0 to 9.0, including from about 5.5 to about 8.5 and about 6.0 to about 8.0.

The cured binder pH was measured according to the following method: A 40 g sample (+/−0.2 g) is cut through the whole thickness of the finished product and then cut into small pieces (about 0.5″×0.5″×0.5″). A predetermined weight w₁ of deionized water is then added to a beaker. The pieces are immersed into the water and mechanically agitated (e.g. mixer or manually by squeezing) so that the water completely wets out the pieces. The pieces are soaked in the water for 5 minutes. After 5 minutes, the pieces are squeezed, and the water is measured for its pH within 3 minutes. The pH of the product is determined as the average of three measurements.

The weight w1 of the deionized water is determined by the LOI (in %) of the product using the formula:

w ₁=LOI*2*40 g

The weight w1 for a product with the LOI of 10% would be 800 g (10*2*40 g=800 g).

As illustrated in FIG. 1, as the pH of the binder composition increases, the color of the cured binder composition dramatically lightens from a dark orange color at an uncured pH of 2.7 to an essentially white color at an uncured pH of 4.03. A significant color change began to occur as the uncured pH approaches 3.5.

FIG. 2 further exemplifies the color change seen in the cured Polyacrylic Acid/Sorbitol/Polyvinyl alcohol (“PAA/S/PVOH”) binder composition as the pH increases, compared to a traditional carbohydrate-based binder composition.

In FIG. 2, the color impact was measured using L*a*b* coordinates, which is a test that was modeled after a color-opponent theory stating that two colors cannot be red and green at the same time or yellow and blue at the same time. FIG. 2 illustrates the b* value (measured with a HunterLab MiniScan EZ instrument), which is the yellow/blue coordinate (yellow when positive, blue when negative). A lower number on this scale indicates less yellowing. As shown in FIG. 2, the b* color value decreases dramatically from above 25 at an uncured pH around 2.8 to between 4 and 7 at an uncured pH range of about 4.1 to 4.3. This reduction in b* color value indicates that any yellow color in the cured binder is much lighter and closer to white, as the line approaches 0. In various exemplary embodiment, the binder composition achieves a b* color value, using L*a*b* coordinates, of less than 45, such as less than 40, less than 35, less than 30, less than 25, less than 20, less than 15, less than 10, and less than 5.

This pH adjustment may be accomplished with the inclusion of organic and/or inorganic bases in an amount sufficient to adjust the pH to a desired level. In some exemplary embodiments, the base is a non-volatile base. Exemplary organic and/or inorganic bases include sodium hydroxide, ammonium hydroxide, and diethylamine, and any kind of primary, secondary, or tertiary amine (including alkanol amines). Alternatively, or in addition, the pH adjustment may be accomplished by incorporating alkaline reclaim or “wash” water, which may have a pH of about 7 to 8.

Accordingly, various aspects of the present application are directed to methods for controlling the color of a cured binder composition by controlling the binder pH. Surprisingly, such an increase in pH has little or no impact on product performance. Such an effect is unexpected, since other polycarboxylic acid and/or carbohydrate-based binder compositions demonstrated the opposite effect, in that increasing the pH 1.0 to 1.5 pH units caused a decrease in performance and increase in undesirable color. Table 1, below, illustrates the recovery data for low density fiberglass insulation boards prepared using both a binder composition in accordance with the present disclosure (PAA/S/PVOH) and a conventional starch-hybrid binder composition, with varying levels on pH increase. The thickness of each product was measured, compressed for about one week, and then released. This was done in both dry (room temperature and about 50% relative humidity) and hot/humid (90 F and 90% relative humidity) conditions. The thickness recovery was then measured and shown below, in Table 1. As the pH was increased due to the addition of wash water (WW) or “reclaimed water,” the boards formed with the PAA/S/PVOH binder composition demonstrated higher thickness recovery than the boards formed using a conventional starch-hybrid binder composition.

TABLE 1 Recovery Data PAA/S/PVOH Starch-hybrid binder Dry Hot/Humid Dry Hot/Humid Binder; pH + 0.0 96% 93% 95% 90% Binder + WW; pH + 0.5 96% 94% 100%  89% Binder + WW; pH + 1.0 92% 91% 96% 82% Binder + WW; pH + 1.5 93% 91% 93% 75%

When in an un-cured state, the pH of the binder composition may range from about 2 to about 5, including all amounts and ranges in between. In some exemplary embodiments, the pH of the binder composition, when in an un-cured state, is about 2.2-4.0, including about 2.5-3.8, and about 2.6-3.5. After cure, the pH of the binder composition may rise to at least a pH of 5.0, including levels between about 6.5 and 7.2, or between about 6.8 and 7.2.

Optionally, the binder may contain a dust suppressing agent to reduce or eliminate the presence of inorganic and/or organic particles which may have adverse impact in the subsequent fabrication and installation of the insulation materials. The dust suppressing agent can be any conventional mineral oil, mineral oil emulsion, natural or synthetic oil, bio-based oil, or lubricant, such as, but not limited to, silicone and silicone emulsions, polyethylene glycol, as well as any petroleum or non-petroleum oil with a high flash point to minimize the evaporation of the oil inside the oven.

In some exemplary embodiments, the aqueous binder composition includes up to about 10 wt. % of a dust suppressing agent, including up to about 8 wt. %, or up to about 6 wt. %. In various exemplary embodiments, the aqueous binder composition includes between 0 wt. % and 10 wt. % of a dust suppressing agent, including about 1.0 wt. % to about 7.0 wt. %, or about 1.5 wt. % to about 6.5 wt. %, or about 2.0 wt. % to about 6.0 wt. %, or about 2.5 wt. % to 5.8 wt. %.

The binder further includes water to dissolve or disperse the active solids for application onto the reinforcement fibers. Water may be added in an amount sufficient to dilute the aqueous binder composition to a viscosity that is suitable for its application to the reinforcement fibers and to achieve a desired solids content on the fibers. It has been discovered that the present binder composition may contain a lower solids content than traditional phenol-urea formaldehyde or carbohydrate-based binder compositions. In particular, the binder composition may comprise 5% to 35% by weight of binder solids, including without limitation, 10% to 30%, 12% to 20%, and 15% to 19% by weight of binder solids. This level of solids indicates that the subject binder composition may include more water than traditional binder compositions. However, due to the high cure rate of the binder composition, the binder can be processed at a high ramp moisture level (about 8%-10%) and the binder composition requires less moisture removal than traditional binder compositions. The binder content may be measured as loss on ignition (LOI). In certain embodiments, LOI is 5% to 20%, including without limitation, 10% to 17%, 12% to 15%, and 13% to 14.5%.

In some exemplary embodiments, the binder composition is capable of achieving similar or higher performance than traditional phenolic or starch-hybrid binder compositions with lower LOI.

In some exemplary embodiments, the aqueous binder composition may also include one or more additives, such as a coupling agent, an extender, a crosslinking density enhancer, a deodorant, an antioxidant, a dust suppressing agent, a biocide, a moisture resistant agent, or combinations thereof. Optionally, the binder may comprise, without limitation, dyes, pigments, additional fillers, colorants, UV stabilizers, thermal stabilizers, anti-foaming agents, emulsifiers, preservatives (e.g., sodium benzoate), corrosion inhibitors, and mixtures thereof. Other additives may be added to the binder composition for the improvement of process and product performance. Such additives include lubricants, wetting agents, antistatic agents, and/or water repellent agents. Additives may be present in the binder composition from trace amounts (such as <about 0.1% by weight the binder composition) up to about 10% by weight of the total solids in the binder composition.

In some exemplary embodiments, the aqueous binder composition is substantially free of a monomeric carboxylic acid component. Exemplary monomeric polycarboxylic acid components include aconitic acid, adipic acid, azelaic acid, butane tetra carboxylic acid dihydrate, butane tricarboxylic acid, chlorendic anhydride, citraconic acid, citric acid, dicyclopentadiene-maleic acid adducts, diethylenetriamine pentacetic acid pentasodium salt, adducts of dipentene and maleic anhydride, endomethylenehexachlorophthalic anhydride, ethylenediamine tetraacetic acid (EDTA), fully maleated rosin, maleated tall oil fatty acids, fumaric acid, glutaric acid, isophthalic acid, itaconic acid, maleated rosin-oxidize unsaturation with potassium peroxide to alcohol then carboxylic acid, malic acid, maleic anhydride, mesaconic acid, oxalic acid, phthalic anhydride, polylactic acid, sebacic acid, succinic acid, tartaric acid, terephthalic acid, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, and trimesic acid.

In various exemplary embodiments, the aqueous binder composition includes a long-chain polyol (e.g., fully or partially hydrolyzed polyvinyl alcohol), a primary crosslinking agent (e.g., polymeric polycarboxylic acid), and a secondary crosslinking agent (e.g. a sugar alcohol). The range of components used in the inventive binder composition according to certain exemplary embodiments is set forth in Table 2.

TABLE 2 Exemplary Range 1 Exemplary Range 2 (% By Weight of (% By Weight of Component Total Solids) Total Solids) Long-chain polyol  5-30 10-20 Crosslinking Agent 50-85 65-80 Short-chain polyol  3-30  5-25 Ratio of COOH/OH 1/0.05-1/5   1/0.3-1/2  Ratio long-chain 0.1/0.9-0.9/0.1 0.4/0.6-0.6/0.4 polyol/short-chain polyol

Aqueous binder compositions according to various exemplary embodiments of the present disclosure may further include a catalyst/accelerator (e.g., sodium hypophosphite), a surfactant, and/or a coupling agent (e.g., silane) are set forth in Table 3.

TABLE 3 Exemplary Range 1 Exemplary Range 2 (% By Weight of (% By Weight of Component Total Solids) Total Solids) Long-chain polyol  5-30 10-20 Crosslinking Agent 50-85 65-80 Short-chain polyol  3-30  5-25 Catalyst 1.0-5.0 2.0-4.0 Coupling agent 0.1-2.0 0.15-0.8  Surfactant 0.01-5.0  0.1-1.0

In some exemplary embodiments, the binder composition is formulated to have a reduced level of water soluble material post-cure as determined by extracting water-soluble materials with deionized water for 2 hours at room temperature using about 1000 g of deionized water per about 1 gram of binder. The higher the level of water soluble material after cure, the more likely it is that a cured material suffers from leaching if/when exposed to water and/or a hot/humid environment. In some exemplary embodiments, the binder composition has no greater than 6 wt. % of water soluble material after cure. In some exemplary embodiments, the binder composition has less than 5.0 wt. % water soluble material after cure, including less than 5.0 wt. %, 4.0 wt. %, 3.0 wt. %, less than 2.5 wt. %, less than 2.0 wt. %, less than 1.5 wt. %, or less than 1.0 wt. %. It has been discovered that reducing the level of water soluble material after cure to no greater than 6.0 wt. %, will improve the tensile strength of the binder composition, as compared to an otherwise similar binder composition having greater than 6.0 wt. %, water soluble material after cure.

TABLE 4 Ambient Hot/humid Tensile/ tensile/ Color Water # PAA Sorbitol PVOH LOI LOI b* soluble % Set point ratio Comp. 52.17% 0 47.83% 37.9 38.3 48.2 4.90% COOH/OH = Ex. 1 1/1.5 (P/S = 1/0) Comp. 95.96% 0 4.04% 38.0 32.0 31.3 51.7% COOH/OH= Ex. 2 1/0.07(P/S = 1/0) Comp. 61.28% 38.72% 0 39.7 40.4 −0.5 6.5% COOH/OH = Ex. 3 1/1.5(P/S = 0/1) Comp. 95.96% 4.04% 0 44.3 38.7 1.5 15.9% COOH/OH = Ex. 4 1/0.1(P/S = 0/1) A 61.84% 27.51% 10.65% 39.1 37.4 44.0 1.5% COOH/OH = 1/1.34(P/S = 0.21/0.79) B 61.84% 8.15% 30.01% 39.5 38.8 48.2 2.6% COOH/OH = 1/1.11 (P/S = 0.72/0.28) C 66.39% 27.51% 6.10% 39.8 39.6 39.9 1.9% COOH/OH = 1/1.13(P/S = 0.13/0.87) D 83.73% 10.17% 6.10% 40.8 33.5 40.0 3.4% COOH/OH = 1/0.41(P/S = 0.29/0.71) E 71.51% 16.30% 12.20% 40.0 38.8 46.4 4.6% COOH/OH = 1/0.82(P/S = 0.34/0.66) F 52.17% 38.72% 9.11% 41.2 39.4 27.2 8.1% COOH/OH = 1/2.05(P/S = 0.14/0.86) G 83.73% 8.15% 8.12% 45.4 38.4 40.6 5.7% COOH/OH = 1/0.39(P/S = 0.41/0.59) H 91.52% 0 0.84% 32.09 26.29 19.47 93.4% COOH/OH = 1/0.02(P/S = 1/0)

The amount of water soluble material remaining in the binder composition after cure may be determined at least in part by the amount of carboxylic acid groups in the binder. Particularly, excess acid groups increase the water-soluble content leads to an increase in water soluble material post-cure. As shown in Table 4, below, Comparative Examples 1 and 2 have COOH/OH ratios that are highly acidic, resulting in an unacceptably high percentage of water soluble material after cure. In contrast, the percentage of water soluble material remaining after cure decreases substantially at COOH/OH ratios of 1/0.1 or less.

It has further been discovered that the total polyol content should contain at least 10 wt. % of one or more short-chain polyols to produce a binder composition with an acceptably low level (e.g., no greater than 6 wt. %) of water soluble material after cure. This is particularly surprising since generally, short-chain polyols, such as sorbitol, have high water solubility. Thus, it would be expected that increasing the level of sorbitol would increase the amount of water soluble material in the binder composition.

In some exemplary embodiments, the binder composition has a viscosity of less than about 400 cP at 30% solids or less, including less than about 300 cP at 30% solids or less, and less than about 200 cP at 30% solids or less. In various exemplary embodiments, the viscosity of the binder composition is no greater than 250 cP at 30% solids or less.

The fibrous products of the present disclosure comprise a plurality of randomly oriented fibers. In certain exemplary embodiments, the plurality of randomly oriented fibers are mineral fibers, including, but not limited to glass fibers, glass wool fibers, mineral wool fibers, slag wool fibers, stone wool fibers, ceramic fibers, metal fibers, and combinations thereof.

Optionally, other reinforcing fibers such as natural fibers and/or synthetic fibers such as carbon, polyester, polyethylene, polyethylene terephthalate, polypropylene, polyamide, aramid, and/or polyaramid fibers may be used in the non-woven fiber mats. The term “natural fiber” as used herein refers to plant fibers extracted from any part of a plant, including, but not limited to, the stem, seeds, leaves, roots, or phloem. Examples of natural fibers suitable for use as the reinforcing fiber material include wood fibers, cellulosic fibers, straw, wood chips, wood strands, cotton, jute, bamboo, ramie, bagasse, hemp, coir, linen, kenaf, sisal, flax, henequen, and combinations thereof. Nonwoven products may be formed entirely of one type of fiber, or they may be formed of a combination of types of fibers. For example, the insulation products may be formed of combinations of various types of glass fibers or various combinations of different inorganic fibers and/or natural fibers depending on the desired application. In certain exemplary embodiments the insulation products are formed entirely of glass fibers.

Having generally described this invention, a further understanding can be obtained by reference to certain specific examples illustrated below which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified.

Example 1

Binder formulations with varying carboxylic acid/hydroxyl ratios and varying polyvinyl alcohol/sorbitol ratios were utilized to form thin boards (425° F. cure temp and 0.125-inch thickness) that were cut into strips. These ratios are depicted below in Table 5. Each board strip was subjected to a 3-point bend test, wherein a load was placed in the middle of each strip and the amount of load the board strip was able to withstand prior to break was measured. The results are depicted in FIG. 3.

TABLE 5 Sample COOH/OH ratio PVOH/Sorbitol ratio 1a 1/0.1 0.1/0.9 1b 1/0.1 0.5/0.5 1c 1/0.1 0.9/0.1 2a  1/0.66 0.1/0.9 2b  1/0.66 0.5/0.5 2c  1/0.66 0.9/0.1 3a 1/1.5 0.1/0.9 3b 1/1.5 0.5/0.5 3c 1/1.5 0.9/0.1

As illustrated in FIG. 3, within each carboxylic acid/hydroxyl group ratio, the flex stress/weight/LOI increased or decreased depending on the polyvinyl alcohol/sorbitol ratio. Flex stress is a three-point bend test (i.e., force until breakage) utilizing a 2″×6″ board with a ⅛″ thickness. The highest flex stress/LOI overall was achieved when the carboxylic acid/hydroxyl group ratio was 1/0.66. Moreover, within this ratio, the flex stress/LOI was further increased when the polyvinyl alcohol/sorbitol ratio was 0.5/0.5. In fact, a polyvinyl alcohol/sorbitol ratio of about 0.5/0.5 demonstrated the highest flex stress within each set of carboxylic acid/hydroxyl group ratios.

The samples were further tested for color impact using L*a*b* coordinates, which is a test that was modeled after a color-opponent theory stating that two colors cannot be red and green at the same time or yellow and blue at the same time. FIG. 4 illustrates the b* value, which is the yellow/blue coordinate (yellow when positive, blue when negative). A lower number on this scale indicates less yellowing. As shown in FIG. 4, compositions that included less long-chain polyol (in this case PVOH) demonstrated less yellowing and an overall improvement in color.

Example 2

Binder compositions with varying COOH/OH and long-chain polyol/short-chain polyol ratios were utilized to form non-woven fiberglass binder impregnated filter (BIF) sheets having a width of 9.5 mm, thickness of 0.5 mm, and a length of 97 mm. The non-woven fiberglass BIF sheets were cured for 3 minutes and 30 seconds at 425° F. The tensile strength, the Loss on Ignition (LOI), tensile strength divided by the LOI (tensile strength/LOI), and b* color value for each sample was determined under ambient conditions and steam (“hot/humid”) conditions. The tensile strength was measured using Instron (Pulling speed of 2 inches/min). The LOI of the reinforcing fibers is the reduction in weight experienced by the fibers after heating them to a temperature sufficient to burn or pyrolyze the binder composition from the fibers. The LOI was measured according to the procedure set forth in TAPPI T-1013 OM06, Loss on Ignition of Fiberglass Mats (2006). To create the hot/humid environment, the filter sheets were placed in an autoclave at 240° F. at a pressure between 400 and 500 psi for 60 minutes.

As illustrated in FIG. 5, the tensile/LOI appeared to generally increase in both ambient and hot/humid conditions when the ratio of short-chain polyol in the composition was increased (within a COOH/OH ratio of 1/0.1). This relationship appears consistent with the level of water solubles remaining in the composition after cure. (FIG. 6). FIG. 6 illustrates that as the ratio of short-chain polyol increases, the percentage of water soluble materials in the composition after cure decreases. Notably, the b* color value also decreases with increases short-chain polyol ratio.

These relationships continue when the COOH/OH ratio is adjusted to 1/1.5, as illustrated in FIGS. 7 and 8. However, notably, the percentage of water soluble materials remaining in the composition after cure is substantially lower at this COOH/OH range. For instance, even in a composition lacking any short-chain polyol, the percentage water soluble material is less than 8.0% and after some short-chain polyol is added, the percentage drops below 5.0%.

As the COOH/OH ratio is adjusted to 1/0.5, 1/0.1, and 1/1, however, although both the percent water soluble material and b* color value similarly decline with increasing ratio of short-chain polyol, both the ambient and hot/humid tensile strengths remained relatively constant regardless of the long-chain/short-chain polyol ratio. See FIGS. 9 through 12. It should be noted, however, that the highest ambient tensile strengths/LOI were demonstrated at long-chain/short-chain polyol ratios of 0.5/0.5 and 0.3/0.7, when the COOH/OH ratio was 1/0.5 (tensile strengths/LOI of about 44 and 45, respectively).

FIG. 13 illustrates the shift in tensile/LOI for filter sheets impregnated with binder compositions having varying COOH/OH ratios from 1/0.1 to 1/10. As illustrated, the optimal tensile/LOI under both ambient and hot/humid conditions can be seen when the COOH/OH ratio is not too low or too high. At both too high or too low COOH/OH ratios, the hot/humid tensile/LOI suffers, which leads to insufficient strength properties.

Example 3

Binder compositions with varying ratios were utilized to form fiberglass insulation board (e.g., ceiling tiles). The insulation boards formed with binder compositions according to the preset application (labeled as PAA/S/PVOH in various ratios of polyacrylic acid/sorbitol/polyvinyl alcohol) were compared to boards formed using both a conventional carbohydrate-based binder composition (“Starch-Hybrid Binder Board”) and a phenol urea formaldehyde binder composition (“PUF Board”). The elastic modulus, compressive strength (delta b), and sag (inches) for each sample was determined under ambient conditions.

As illustrated in FIG. 14, each of the PAA/S/PVOH insulation board samples demonstrated improved Flexural Elastic Modulus, as compared to both conventional carbohydrate-based binder compositions and phenol urea formaldehyde-based binder compositions. PAA/S/PVOH 50:20:30 and PAA/S/PVOH 60:10:30 demonstrated the greatest improvement, with Flexural Elastic Modulus levels at about 70 psi and 68 psi, respectively. In contrast, the PUF Board demonstrated a Flexural Elastic Modulus of about 46 psi and the Starch-Hybrid Binder Board demonstrated an elastic modulus of about 31 psi. In some exemplary embodiments, an insulation board with a thickness of about 1 inch and a density of about 6 lbs/ft³ according to the present inventive concepts achieves an elastic modulus of at least 40 psi, including at least 45 psi, at least 50 psi, and at least 55 psi.

FIG. 15 illustrates the sag observed by various 4′×4′ insulation board panels after a set number of days in a hot/humid environment at 90 F/90% rH (relative humidity).

As shown in FIG. 15, the PAA/S/PVOH binder compositions having lower levels of PVOH (i.e., PAA/S/PVOH 60:20:15 and PAA/S/PVOH 75:10:15) demonstrated less sag under hot/humid conditions than both PUF Board and Starch-Hybrid Binder Board. This indicates that lowering the long-chain polyol in the binder compositions may help improve the hot/humid performance in applications that need very high standard of hot and humid performances.

FIG. 16 illustrates the compressive strength at 10% deformation of fiberglass board products of different binders and LOI %. The test was performed on 6″×6″ insulation boards, with a thickness about 1″ and density about 6 lb/ft³, according to ASTM method C-165. As illustrated in FIG. 16, the compressive strength of the insulation boards formed with a PAA/S/PVOH binder exceeded that of insulation boards formed with both a starch-hybrid binder and a PUF binder, demonstrating compressive strengths of about 260 lbs/ft² to over 500 lbs/ft². In some exemplary embodiments, a 6″×6″ insulation board with a thickness of about 1 inch according to the present inventive concepts achieves a compressive strength of at least 200 lbs/ft², including at least 300 lbs/ft², at least 400 lbs/ft², and at least 500 lbs/ft².

FIG. 17 illustrates the bond strength at break of fiberglass board products of different binders and LOI %. The test measures the strength in Z direction of 6″×6″ insulation boards with a thickness of about 1″ and density of about 6 lb/ft³. As illustrated in FIG. 17, the bond strength of insulation boards formed with PAA/S/PVOH binders exceeded that of insulation board formed with a starch-hybrid binder. Additionally, the insulation boards formed with PAA/S/PVOH binders demonstrated a comparable bond strength to insulation boards formed with a PUF binder, demonstrating bond strengths of about 10 lbs/ft² to over 15 lbs/ft². In some exemplary embodiments, a 6″×6″ insulation board with a thickness of about 1 inch according to the present inventive concepts achieves a bond strength of at least 7.5 lbs./ft²/LOI, including at least 10 lbs./ft²/LOI, at least 12.5 lbs./ft²/LOI, and at least 15 lbs./ft²/LOI.

It will be appreciated that many more detailed aspects of the illustrated products and processes are in large measure, known in the art, and these aspects have been omitted for purposes of concisely presenting the general inventive concepts. Although the present invention has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the present disclosure and various changes and modifications can be made to adapt the various uses and characteristics without departing from the spirit and scope of the present invention as described above and set forth in the attached claims. 

What is claimed is:
 1. An aqueous binder composition comprising: at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000 Daltons; a cross-linking agent comprising at least two carboxylic acid groups; and a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000 Daltons, wherein said binder composition has a pH after cure between 5 and 9 and achieves a b* color value, using L*a*b* coordinates, of less than
 45. 2. The aqueous binder composition of claim 1, wherein said cross-linking agent is a polymeric polycarboxylic acid.
 3. The aqueous binder composition of claim 1, wherein said cross-linking agent is present in the binder composition in an amount from about 50 wt. % to about 85 wt. %, based on the total solids content of the aqueous binder composition.
 4. The aqueous binder composition of claim 1, wherein said cross-linking agent is present in the binder composition in an amount from about 65 wt. % to about 80 wt. %, based on the total solids content of the aqueous binder composition.
 5. The aqueous binder composition of claim 1, wherein said long-chain polyol is selected from the group consisting of polyvinyl alcohol and polyvinyl acetate.
 6. The aqueous binder composition of claim 1, wherein said long-chain polyol is present in the binder composition in an amount from about 5 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition.
 7. The aqueous binder composition of claim 1, wherein said short-chain polyol comprises one or more of a sugar alcohol, 2,2-bis(methylol)propionic acid, tri(methylol)propane, and a short-chain alkanolamine.
 8. The aqueous binder composition of claim 7, wherein said short-chain polyol comprises a sugar alcohol selected from the group consisting of glycerol, erythritol, arabitol, xylitol, sorbitol, maltitol, mannitol, iditol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritol, syrups thereof, and mixtures thereof.
 9. The aqueous binder composition of claim 1, wherein said short-chain polyol is present in the binder composition in an amount from about 3 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition.
 10. An insulation product comprising: a plurality of randomly oriented fibers; and an aqueous binder composition at least partially coating said fibers, said binder composition comprising: at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000 Daltons; a cross-linking agent comprising at least two carboxylic acid groups; and a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000 Daltons, wherein said binder composition has a pH after cure between 5 and 9 and achieves a b* color value, using L*a*b* coordinates, of less than
 45. 11. The insulation product of claim 10, wherein the fibers comprise one or more of mineral fibers, natural fibers, and synthetic fibers.
 12. The insulation product of claim 10, wherein the fibers comprise glass fibers, mineral wool fibers, or a mixture thereof.
 13. The insulation product of claim 10, wherein when said insulation product has a thickness of about 1 inch and a density of about 6 lbs/ft³, said insulation product has a flexural elastic modulus of at least 40 psi.
 14. The insulation product of claim 10, wherein when said insulation product has a thickness of about 1 inch and a density of about 6 lbs/ft³, said insulation product has a compressive strength at 10% deformation of at least 200 lbs./ft².
 15. The insulation product of claim 10, wherein a ratio of molar equivalents of carboxylic acid groups to hydroxyl groups in the binder composition is from about 1/0.05 to about 1.0/5.0.
 16. A method for controlling color in insulation products formed using a formaldehyde-free binder composition, comprising: preparing a formaldehyde-free binder composition comprising: at least one long-chain polyol having at least two hydroxyl groups and a number average molecular weight of at least 2,000 Daltons; and a short-chain polyol having at least two hydroxyl groups and a number average molecular weight less than 2,000 Daltons; curing said binder composition to achieve a b* color value, using L*a*b* coordinates, of less than 45 and a cured binder pH of between 5 and
 9. 17. The method of claim 16, wherein said binder composition further comprises a cross-linking agent, comprising at least two carboxylic acid groups.
 18. The method of claim 17, wherein said cross-linking agent is a polymeric polycarboxylic acid.
 19. The method of claim 17, wherein a ratio of molar equivalents of carboxylic acid groups to hydroxyl groups is from about 1/0.05 to about 1.0/5.0.
 20. The method of claim 16, wherein said long-chain polyol is selected from the group consisting of polyvinyl alcohol and polyvinyl acetate.
 21. The method of claim 16, wherein said long-chain polyol is present in the binder composition in an amount from about 5 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition.
 22. The method of claim 16, wherein said short-chain polyol comprises one or more of a sugar alcohol, 2,2-bis(methylol)propionic acid, tri(methylol)propane, and a short-chain alkanolamine.
 23. The method of claim 16, wherein said short-chain polyol is present in the binder composition in an amount from about 3 wt. % to about 30 wt. %, based on the total solids content of the aqueous binder composition.
 24. The method of claim 16, wherein said binder composition includes a ratio of long-chain polyol to short-chain polyol is from about 0.1/0.9 to about 0.9/0.1.
 25. The method of claim 16, wherein prior to curing, the pH of the binder composition is adjusted by 0.25 to 1.5 pH units.
 26. The method of claim 25, wherein said pH is adjusted by the addition of one or more of a non-volatile base and alkaline water.
 27. The method of claim 1, wherein said binder composition achieves a b* color value, using L*a*b* coordinates, of less than
 40. 28. The method of claim 1, wherein said binder composition has an un-cured pH of about 2 to about
 5. 29. The method of claim 1, wherein said binder composition has a cured pH of between 6.0 and 8.0.
 30. The method of claim 16, wherein when said insulation product has a thickness of about 1 inch and a density of about 6 lbs/ft³, said insulation product has a flexural elastic modulus of at least 40 psi.
 31. The method of claim 16, wherein when said insulation product has a thickness of about 1 inch and a density of about 6 lbs/ft³, said insulation product has a compressive strength at 10% deformation of at least 200 lbs./ft².
 32. The method of claim 16, wherein when said insulation product has a thickness of about 1 inch and a density of about 6 lbs/ft³, said insulation product has a bond strength at break of at least 7.5 lbs./ft²/LOI. 